1. Field of the Invention
The present invention relates to a display device and it particularly relates to a liquid crystal display device capable of improving the screen brightness.
2. Description of the Related Art
A conventional liquid crystal display device includes a TFT substrate having a pixel electrode, thin film transistors (TFT), etc. formed in a matrix; a counter substrate disposed in facing relation to the TFT substrate and having a color filter, etc. formed at portions corresponding to the pixel electrodes of the TFT substrate; and liquid crystals put between the TFT substrate and the counter substrate. Images are formed by controlling the transmittance of light for every pixel by liquid crystal molecules.
Since liquid crystal display devices are flat and light in weight, their application use has been extended in various fields. Small-sized liquid crystal display devices have been used generally for mobile phones and DSOs (Digital Still Cameras). The liquid crystal display devices involve a problem of a so-called viewing angle characteristics in which contrast or color changes when a screen is viewed from the oblique direction to the screen. For the viewing angle characteristics, IPS (In Plane Switching) liquid crystal display device (hereinafter referred as a IPS) have excellent characteristics.
While IPS include various IPS types, liquid crystal display devices of a type in which an insulating film is formed on a rectangular first electrode, over which a comb-shaped second electrode is disposed have been used generally so far. When the first electrode is a pixel electrode, the second electrode is a common electrode and, on the contrary, when the first electrode is a common electrode, the second electrode is a pixel electrode.
At the end of the comb-shaped electrode of the second electrode, a domain tends to be generated by reverse rotation of liquid crystal molecules. Particularly, touch panel systems have been popularized recently and, in this system, the surface of a liquid crystal display panel is touched by a finger or the like. Then, the liquid crystal molecules rotate by the pressure and it take a time to return to the initial state, to cause a problem of deteriorating image quality. The problem is hereinafter referred to as pressing domain. In order to overcome the problem, JP-A-2000-330123 describes a configuration of preventing generation of pressing domain by bending the top ends of the comb-teeth in a range of larger than 1° and smaller than 90°.